1. Statement of the Technical Field
The inventive arrangements relate to protective systems for electronic devices, and more particularly to systems designed to protect users of multimode communication devices from potentially dangerous outputs.
2. Description of the Related Art
Multimedia devices, such as mobile phones and mobile computing devices with telephone functionality, are often configured to produce an acoustic output. Acoustic shock is a temporary or permanent disturbance of the functioning of the ear or of the nervous system that may be caused to a user of a telephone earphone by a sudden sharp rise in the acoustic pressure produced by the device. Various methods and systems have been suggested for reducing the risk of acoustic shock. One solution involves the use of two separate speakers. A large high output power speaker is used for ringing tones, signaling tones, and hands-free phone operation. A smaller, lower output power, speaker is used during normal telephone calls where the device is held to the user's ear. In such systems, the large, high-power speaker is commonly positioned in or on the device at a location which is spaced apart from the smaller speaker so that the larger speaker is not too close the user's ear during normal phone conversations. For example, the output of the larger speaker can be emitted from a side of the device opposed to the side where the output of the smaller speaker is emitted. Alternatively, the larger speaker can be positioned at an end of the device opposed from the end where the smaller earphone speaker is located. With the foregoing arrangements, the user can place the portion of the device containing the smaller speaker directly adjacent to their ear, while minimizing the risk that an unexpected output (ringing or hand-free phone audio) from the larger, more powerful speaker, will cause acoustic shock.
Another solution to the problem involves selectively controlling the output power of the larger, higher power, speaker so that its sound pressure output is slowly ramped up over a period of time. Certain improvements to this approach have been suggested in EP 1,696,695 whereby ramping is temporarily suspended during periods of time when audio output is momentarily silent. Other solutions to the problem involve sensors and control software which are intended to help the device determine when it is positioned at a location adjacent to a human ear.